1. Government Exorcist (TSotS) - very efficient character which can target your opponent's strongest terror character to not participate, forcing them to reserve more for defense.
2. Shadow Team (SoM) - removing a combat from every single opponent's character is huge and makes them a lot easier to kill. It's still vulnerable to terror, but a Holy Rosary or other out-of-faction answers can help protect him.
3. Small Price to Pay (Core) - early on, this can be crucial to slow down your opponent, and since it can either wound or drive insane, you can choose which option is best against any given deck.
4. Marshall Greene (THBtS) - the additional willpower can be beneficial to nullify the terror struggle at one story, since willpower is harder to remove. He's also pretty efficient and hard to get rid of.
5. Paul LeMond (Core) - classic super-weenie but very flexible early and late game.
6. San Marco Basilica (TiV) - Free ready for one character and cheap ready for multiple characters, and it's immune to most popular support control.
7. Shotgun Blast (Core) - Similar to Cthulhu's Deep One Assault (Core), this only targets characters, but it isn't loyal! A very good early game tempo control card.
8. The Iron Cross (TiV) - I didn't think much of this until I realized that it's a Disrupt, now it's one of Agency's best attachments since an opponent has to use twice as many effects to get rid of the character.
9. The Company (SoK) - very efficient even outside of a government deck, but in a government deck giving all your government characters toughness is amazing
10. Undercover Security (Core) - cheap and efficient with willpower, combat, and investigation.
Behind Bars (SotD) - Great for a rush deck to get early unopposed, or to fend of that impossible AO should he appear.Torch the Joint (SoM) - One of the only cards in the game that destroys a resource.
- Eliot Ness' Handcuffs (TBJ) - Keywords are critical sometimes. Fast, willpower, invulnerability, toughness, all can make a difference, especially when you have nice wounding effects to make use of.
- James Logan (WitD) - a cord for combo-lovers, he's expensive, but when you can attach two cards to him for free, he becomes much more efficient.
- Daemonolatreia (LR) - probably one of the few attachment support cards I would consider running in Agency, just because it eliminates mid-story surprises.
- Repo Man (TAD) - taking over an opponent's location can be huge, and often combat struggles can be wasted if your opponent doesn't commit. This is one of the only ways to take control of a location in the game.
- Shotgun (Core) - Suddenly your opponent must account for potentially 2 wounds (one from this and one from combat), and he can't commit a character that he wants to lose.
- Intervention (TSC) - this surprise character can mean wounding and an additional success token; this has an advantage over Master of the Myths and Black Dog since it can be used on offense as well.
- Military Bike (TPtY) - While it is an attachment, it is very satisfying to have one of your characters do double duty, especially if they have a great "when it commits" ability like Priest of Two Faiths (TSC) or Obscure Linguist (AoA).
- Beneath the Burning Sun (SoA) - A staple card for a Day deck. (I like The Setting Sun (TH) more though.)
- Catastrophic Explosion (TGS) - If you have enough high-skill characters in play, this can be a great partial reset to get the board under control.